With two 180 Ah lead-acid batteries he could not last a day without shore power. So the question was not which battery to fit, but how he could stay away from the dock for longer.

Built to the standards of its time

A Kent 27 from that era was built to what was usual and possible back then. That is no criticism of the builder. Those standards have simply moved on.

Two things have changed. Over the past decades, more and more electrical appliances have come on board, so the demand for power has grown considerably. And installations have become smarter, with monitoring and charging technology working together; lithium too has come a long way in leisure boating in recent years. The existing installation was not designed for that. So rather than build around it, I removed the old installation completely.

The old electrical installation of the Kent 27, during dismantling
The old installation, already partly dismantled.

First calculate, then build

Before a single cable is pulled, it is important to look carefully at what the boat needs. I do that in four steps.

1

Consumption

What is on board, and what does it draw in a day?

2

Cruising profile

How long does the owner want to stay off shore power?

3

Battery bank and charging

How much capacity, and how do you recharge: alternator, shore and solar?

4

Design

Which components, where they go and how the cabling runs.

That way everything is settled before anything is mounted, and you avoid surprises on board.

What was done

At the back of the boat a new electrical panel was built, holding most of the components. Lithium is one part of it: the two lead-acid batteries were replaced by two Victron 12V 200 Ah lithium batteries, with a Lynx Smart BMS that monitors them, a Lynx Distributor as the main DC bus and a buck-boost that charges the batteries from the alternator underway. The cable lugs are crimped and finished with heat-shrink.

Diagram of the new installation in the Kent 27Shore power runs through the MultiPlus to the 230V loads and the main DC bus. The alternator charges through the buck-boost, the solar panels through a charge controller. The main DC bus, a Lynx Distributor, feeds the 12V loads and is connected through the Lynx Smart BMS to the battery bank of two 200 Ah lithium batteries. The Cerbo with touchscreen at the helm reads out the system and sets the charge currents.Shore power230V at the dockAlternatoron the engineSolar panelsvia charge controllerCerbo + touchscreenat the helmMultiPlusinverter and chargerBuck-boostcharging via alternatorLynx Smart BMSmonitors the batteries230V loadscoffee machine, chargers12V loadslights, pumpsBattery bank2 × 200 Ah lithium, 12VMAIN DC BUSLynx Distributor230V AC12V DCmonitoring and control signal
How the new installation fits together. Schematic, not to scale. Scroll sideways to see the whole diagram.
Building the new electrical panel at the back of the Kent 27
The new panel during the build.
Victron lithium batteries with Lynx Smart BMS and Lynx Distributor in the Kent 27
The lithium batteries with the BMS and the main DC bus.

At the helm sits the heart of the installation: a Victron Cerbo with a 7-inch touchscreen. The whole system can be read on it, and it is used to set the charge current from the alternator, shore power, the MultiPlus and the solar panels.

Victron Cerbo touchscreen at the helm of the Kent 27
The touchscreen at the helm, next to the gauges.

What it delivers

± 22 hours Without shore power, before
± 90 hours Without shore power, now

Where the owner used to need shore power again after one night, he can now go 3 to 5 days without it.

That is not down to the lithium batteries alone. Almost the full capacity of lithium is usable, against roughly half for lead-acid, which explains about a doubling. The rest has to come from the installation as a whole: a set-up based on his consumption and how he cruises, and a screen at the helm showing how much energy is left in the batteries and what is being used at that moment. So he can manage his consumption himself.

And life on board is simply more comfortable. He can make a cup of coffee without worrying that the machine draws too much power.

Want to stay away from the dock for longer?

An onboard consultation is free and honest. I first look at your consumption and how you cruise; then you know what that takes, and whether lithium is part of it.

Book an onboard consultation →